Catheters and methods for intracardiac electrical mapping

ABSTRACT

A method and system capable of identifying ectopic foci, rotors, or conduction pathways involved in reentrant arrhythmias within cardiac tissue, and then treating identified ectopic foci, rotors, and/or pathways with either lethal or sub-lethal temperatures. The system includes a medical device having one or more mapping elements and one or more treatment elements, and a computer programmable to identify ectopic foci and rotors based at least in part on signals received from the one or more mapping elements at one or more locations.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of patent application Ser. No.13/749,298, filed Jan. 24, 2013, entitled CATHETERS AND METHODS FORINTRACARDIAC ELECTRICAL MAPPING and is related to and claims priority toU.S. Provisional Patent Application Ser. No. 61/684,380, filed Aug. 17,2012, entitled CATHETERS AND METHODS FOR INTRACARDIAC ELECTRICALMAPPING, the entirety of which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

TECHNICAL FIELD

The present invention relates to a method and system for cardiac mappingand ablation.

BACKGROUND

A cardiac arrhythmia is a condition in which the heart's normal rhythmis disrupted. There are many types of cardiac arrhythmias, includingsupraventricular arrhythmias that begin above the ventricles (such aspremature atrial contractions (PACs), atrial flutter, accessory pathwaytachycardias, atrial fibrillation, and AV nodal reentrant tachycardia(AVNRT)), ventricular arrhythmias that begin in the lower chambers ofthe heart (such as premature ventricular contractions (PVCs),ventricular tachycardia (VT), ventricular fibrillation, and long QTsyndrome), and bradyarrhythmias that involve slow heart rhythms and mayarise from disease in the heart's conduction system. Further, cardiacarrhythmias may be classified as reentrant or non-reentrant arrhythmias.In reentrant arrhythmias, the propagating wave of bioelectricity thatnormally spreads systematically throughout the four chambers of theheart instead circulates along a myocardial pathway and around anobstacle (reentry point) or circulates freely in the tissue as a scrollwave or spiral (referred to herein as “rotors”). In non-reentrantarrhythmias, propagation of the normal bioelectricity wave may beblocked or initiated at abnormal (ectopic) locations.

Certain types of cardiac arrhythmias, including ventricular tachycardiaand atrial fibrillation, may be treated by ablation (for example,radiofrequency (RF) ablation, cryoablation, ultrasound ablation, laserablation, and the like), either endocardially or epicardially. However,a physician must first locate the point of reentry, ectopic focus, orregions of abnormal conduction to effectively treat the arrhythmia.Unfortunately, locating the best site for ablation has proven to be verydifficult, even for the most skilled physicians.

Cardiac electrical mapping (mapping the electrical activity of the heartthat is associated with depolarization and/or repolarization of themyocardial tissues) is frequently used to locate an optimal site forablation, for instance, a reentry point, ectopic focus, or a site ofabnormal myocardium. However, the source of an arrhythmia may bedifficult to determine based upon the sensed electrogram morphology. Inaddition to signals emanating from the local myocardium, the electrogrammorphology may include fractionation due to poor electrode contact,electrode design, or complex electrical activity in the vicinity of theelectrodes. The signals may also include “far-field” content fromdistant tissues (such as detection of ventricular activity on atrialelectrodes) or the signal may be attenuated due to disease, ischemia, ortissue necrosis. Further, ablation of one or more identified sites mayalso be problematic. To date, such ablations require either substantialtrial and error (for example, ablation of all sources of complexfractionated electrograms) or the use of separate mapping and ablationdevices (complex mapping systems utilizing multielectrode arrays orbaskets may be used to identify an ablation site, but cannot also beused to ablate the tissue). Therefore, a system and method are desiredthat not only streamline the site identification and ablation processes,but also combine mapping and ablation functionality.

SUMMARY

The system and method of the present application provides anon-ambiguous representation of the electrical activity of themyocardium at each particular site within or on the heart, improvedmeans for searching for and testing potential ablation sites includingboth ectopic foci and rotors, and both mapping and treatmentfunctionality. The non-ambiguous representation of local myocardialdepolarization, repolarization timing, and action potential duration isenabled through the use of electrodes that are able to record localmonophasic action potentials (MAPs).

The system may generally include a medical device defining a distal endincluding a plurality of mapping elements and a treatment element, and acontrol unit in communication with the medical device and programmableto identify a source of electrical conduction of interest within cardiactissue based at least in part on signals received from the plurality ofmapping elements at one or more tissue locations and programmable totreat the source of electrical conduction of interest by activating thetreatment element. The treatment element may be an expandable element,such as a balloon defining an anterior face, the plurality of mappingelements being affixed to the anterior face of the balloon. Theplurality of mapping elements may be arranged in a radially symmetricalpattern. Further, the balloon may have a substantially concentric spiralconfiguration when expanded. Alternatively, the distal end of the devicemay include one or more array arms, and each of which may include afirst portion and a second portion, the first portion being in a planethat is substantially orthogonal to the longitudinal axis of the device.The one or more tissue areas are composed of cells, and the plurality ofmapping elements may selectively transmit energy capable of ablationand/or electroporation of the cells. Further, the treatment element mayselectively transmit energy capable of adjusting the temperature of theone or more tissue areas to a sub-lethal temperature, ablating the oneor more tissue areas, and/or electroporating the cells of the one ormore tissue areas. The device may further comprise a plurality oftreatment elements, with each treatment element selectively transmittingenergy capable of ablation and/or electroporation of cells. Each of theplurality of mapping elements may record monophasic action potentials,such that at least one of depolarization timing, repolarization timing,action potential morphology, and action potential duration isunambiguously determined.

The method of locating and treating a source of electrical conductionwithin cardiac tissue may generally include the following steps: (a)positioning one or more mapping elements affixed to a distal end ofmedical device in contact with cardiac tissue at a first position, themedical device being in communication with a control system including acomputer having a display and programmable to execute algorithms, thecardiac tissue being composed of cells; (b) executing computeralgorithms to determine directional and morphological features of theelectrical conduction of interest based at least in part on signalsreceived by the computer from the one or more mapping elements at thefirst position; (c) displaying on the computer display a suggestedsecond position at which the one or more mapping elements should beplaced in contact with the cardiac tissue; (d) repositioning the one ormore mapping elements at the second position; (e) executing computeralgorithms to determine directional and morphological features of theelectrical conduction of interest based at least in part on signalsreceived by the computer from the one or more mapping elements at thesecond position; (f) repeating steps (a)-(e) until a source or pathwayof the electrical conduction of interest is located; and (g) activatingone or more treatment elements in contact with the cardiac tissue cellsto treat the cells at a non-lethal temperature and disrupt the source orpathway of the electrical conduction of interest. Treating the cells mayinclude cooling or heating the cardiac cells at the source or pathway ofelectrical conduction of interest to a non-lethal temperature. Themethod may further include treating the cardiac cells at the source orpathway of the electrical conduction of interest at a lethaltemperature, which may include cryoablation, tissue cooling, applyingradiofrequency energy, applying laser energy, applying microwave energy,applying laser energy, and/or applying ultrasound energy. Additionallyor alternatively, the method may further include electroporating thecardiac cells at source or pathway of the electrical conduction ofinterest with pulses of high voltage energy. Electroporation may befollowed by delivering to the cardiac cells at the source or pathway ofthe electrical conduction of interest genes, proteins, drug therapysubstances, agents that modify the behavior of the cells, andcombinations thereof. The cardiac cells at the source or pathway of theelectrical conduction of interest may be treated at a lethal temperatureonly after treating the cardiac cells at the source or pathway of theelectrical conduction of interest at a non-lethal temperature.Furthermore, treating the cardiac cells at the source or pathway ofelectrical conduction of interest at a lethal temperature may terminatethe electrical conduction of interest.

Alternatively, the method may include: (a) positioning one or moremapping elements affixed to a distal end of a medical device in contactwith cardiac tissue at a first position, the medical device being incommunication with a control system including a computer having adisplay, the cardiac tissue being composed of cells; (b) executingcomputer algorithms to determine directional and morphological featuresof the electrical conduction of interest based at least in part onsignals received by the computer from the one or more mapping elementsat the first position; (c) displaying on the computer display asuggested second position at which the one or more mapping elementsshould be placed in contact with the cardiac tissue; (d) repositioningthe one or more mapping elements at the second position; (e) executingcomputer algorithms to determine directional and morphological featuresof the electrical conduction of interest based at least in part onsignals received by the computer from the one or more mapping elementsat the second position; (f) repeating steps (a)-(e) until a the sourceof the electrical conduction of interest is located; (g) activating oneor more treatment elements in contact with the cardiac tissue cells totreat the cells at a non-lethal temperature; and (h) if (g) disrupts thesource or pathway of the electrical conduction of interest, activatingthe one or more treatment elements in contact with the cardiac tissuecells to perform at least one of treating the cells with a lethaltemperature and electroporating the cells.

The present invention advantageously provides a method and system for,with a single device, obtaining a non-ambiguous representation ofdepolarization and repolarization at each particular site within or onthe heart, searching for and testing potential ablation sites thatinclude ectopic foci, rotors, or conduction pathways involved inreentrant arrhythmias and ablating identified ectopic foci, rotors,and/or pathways.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and theattendant advantages and features thereof, will be more readilyunderstood by reference to the following detailed description whenconsidered in conjunction with the accompanying drawings wherein:

FIG. 1 shows a system in accordance with the present invention;

FIG. 2 shows a stylized representation of a distal end of a medicaldevice placed substantially centered on an ectopic focus;

FIG. 3 shows a stylized representation of a distal end of a medicaldevice placed substantially centered on a rotor;

FIG. 4 shows a stylized representation of a distal end of a medicaldevice placed substantially on a reentrant pathway;

FIG. 5 shows a stylized representation of a distal end of a medicaldevice placed a distance from an ectopic focus;

FIG. 6 shows a stylized representation of a distal end of a medicaldevice placed a distance from a rotor;

FIG. 7 shows a first embodiment of a distal end of a medical device withmapping and treatment functionality;

FIG. 8 shows a second embodiment of a distal end of a medical devicewith mapping and treatment functionality;

FIG. 9 shows a third embodiment of a distal end of a medical device withmapping and treatment functionality;

FIG. 10 shows a fourth embodiment of a distal end of a medical devicewith mapping and treatment functionality;

FIG. 11 shows a cross section of a first embodiment of a mapping elementsuch as in FIG. 7, 8, or 9;

FIG. 12 shows a cross section of a second embodiment of a mappingelement such as in FIG. 7, 8, or 9;

FIG. 13 shows a perspective view of a third embodiment of a mappingelement such as in FIG. 10; and

FIG. 14 shows a fifth embodiment of a distal end of a medical devicewith mapping and treatment functionality.

DETAILED DESCRIPTION OF THE INVENTION

Now referring to FIG. 1, a system 10 in accordance with the presentinvention is shown. The system 10 generally includes a medical device 12for mapping and/or treating an area of tissue and a console 14 thathouses various system 10 controls. The system 10 may be adapted forradiofrequency (RF) ablation and/or phased radiofrequency (PRF)ablation, cryoablation, ultrasound ablation, laser ablation, microwaveablation, or other ablation methods or combinations thereof.

The device 12 may be a catheter with mapping and treatment functionalitygenerally including a handle 16, an elongate body 18 having a distalportion 20 and a proximal portion 22, one or more mapping elements orsensors 24, and one or more treatment elements 26. The device 12 mayhave a longitudinal axis 28. The distal portion 20 of the device 12 mayinclude an expandable element (such as a balloon or wire mesh), adeformable coil or concentric spiral (as shown in FIG. 7), or otherarray on which mapping 24 and treatment elements 26 may be disposed (forexample, as shown in FIG. 8). Alternatively, the distal portion 20 ofdevice 12 may be straight, such as a focal catheter that may be bendableto an approximately 90-degree angle (as shown in FIG. 9). The mapping 24elements may be sensors or electrodes capable of sensing electricalactivity within the myocardial cells as the cells polarize anddepolarize, such as monophasic action potential (MAP) electrodes. Thedevice 12 may also include one or more reference electrodes 30. Thetreatment elements 26 may be electrodes capable of transmitting thermalenergy, and may be larger (that is, have more surface area) than themapping 24 electrodes. Additionally or alternatively, the treatmentelements 26 may include an expandable treatment element 26 such as acryoballoon. Further, the device 12 may include one or morethermoelectric cooling elements.

The elongate body 18 of the device 12 may include one or more lumens 32.If the device 12 is a cryoablation catheter, for example, the elongatebody 18 may include a main lumen, a fluid injection lumen in fluidcommunication with the coolant reservoir 34, and a fluid return lumen influid communication with the coolant return reservoir 36. In someembodiments, one or more other lumens may be disposed within the mainlumen, and/or the main lumen may function as the fluid injection lumenor the fluid return lumen. If the ablation catheter includesthermoelectric cooling elements or electrodes capable of transmittingradiofrequency (RF), ultrasound, microwave, electroporation energy, orthe like, the elongate body 18 may include a lumen in electricalcommunication with an energy generator 38 and/or a power source 40.

The console 14 may be in electrical and fluid communication with themedical device 12 and include one or more fluid (such as coolant orsaline) reservoirs 34, fluid return reservoirs 36, energy generators 38(for example, an RF or electroporation energy generator), and computers42 with displays 44, and may further include various other displays,screens, user input controls, keyboards, buttons, valves, conduits,connectors, power sources, and computers for adjusting and monitoringsystem 10 parameters. The computer 42 may be in electrical communicationwith the one or more mapping elements 24 and/or the one or moretreatment elements 26 and programmable to execute an algorithm forlocating one or more optimal treatment areas. For example, the computermay assess arrhythmia morphology and directionality using activationtiming signals from the one or more mapping elements 24. Based on thecalculated morphology and directionality, the computer may thendetermine one or more optimal treatment sites (for example, as shown inFIGS. 5 and 6) and communicate those sites, via one or more displays orscreens, to the user.

Once an optimal treatment site is located, and the medical device 12positioned in contact with this site, the one or more treatment elements26 may be activated to treat the site. As a non-limiting example, thesystem 10 may be configured for use in cryoablation procedures. Forexample, the device 12 may include a cryoballoon as the treatmentelement 26. Once an optimal treatment site is located, the medicaldevice 12 may be placed in contact with the treatment site and thetreatment element 26 activated to cool the treatment site to asub-lethal temperature (or heated to a sub-lethal temperature, ifnon-cryogenic energy modalities are used). If the application of thesub-lethal temperature abates, disrupts, or temporarily terminates thearrhythmia, the user may then choose to increase the cooling effect, orlower the temperature, of the one or more treatment elements 26 in orderto permanently ablate the tissue of the treatment site (or raise thetemperature to a lethal temperature, if non-cryogenic energy modalitiesare used). Thus, alternatively, the user may choose to ablate thetreatment site once it has been located and confirmed as an accuratetarget. Additionally or alternatively, once an optimal treatment site islocated, the medical device 12 may be placed in contact with thetreatment site and activated to transmit short pulses of high voltage inorder to electroporate the cells of the treatment site. Thiselectroporation may be used to disable cells, ablate cells, or preparecells for subsequent therapies such as gene delivery, protein delivery,or other therapeutic agent or substance intended to modify the behaviorof the cells.

Now referring to FIGS. 2 and 3, stylized representations of a distalportion 20 of a medical device 12 (depicted as a rectangle) placedsubstantially centered on an ectopic focus and a rotor are shown,respectively, on cardiac tissue 50. In FIG. 2, the small black circlerepresents the center of the focus 46A. Likewise, in FIG. 3, the smallblack circle represents the position of rotation of the rotor 48A(which, for simplicity, will be referred to as the “center” 48A of therotor 48). Referring to FIG. 4, a stylized representation of a distalportion 20 of a medical device 12 placed substantially within areentrant pathway 52 is shown. The stylized distal portion 20 shown inFIGS. 2-4 may represent any configuration, such as a coil or concentricspiral (for example, as shown in FIG. 7), a crossed-arm array (forexample, as shown in FIG. 8), or a linear distal portion 20 (forexample, as shown in FIG. 9). For simplicity, the distal portion 20 isdepicted as a rectangle in FIGS. 2-4.

In FIG. 2, a small black circle is shown within the rectangle,representing a distal portion 20 of a medical device 12 beingsubstantially centered above the center 46A of an ectopic focus 46. Thedashed arrows represent propagating waves of bioelectricity emanatingfrom the center 46A of the ectopic focus 46 in an outward directionthrough cardiac tissue 50. In FIG. 3, a small black circle is shownwithin the rectangle, representing a distal portion 20 of a medicaldevice 12 being substantially centered above the center 48A of the rotor48. The arrows represent a pattern of propagating waves ofbioelectricity from the center (position of rotation 48A), with smallerarrows representing a higher frequency and larger arrows representing alower frequency. The direction of the arrow indicates the direction ofthe wave. In FIG. 4, the rectangle represents the distal portion 20 of amedical device 12 being positioned substantially on a reentrant loop 52.The pattern of propagating waves in the rotor 48 may be a spiral, scrollwave, or other nonlinear pattern, and the location of the center 48A ofthe rotor may change. The propagating waves may move outward from thecenter 46A of an ectopic focus 46 in any direction or in any patternaway from the center 48A in a rotor 48. For reentrant loops 52, theelectrical conduction may be in a repeating circuit with or without theinvolvement of the tissue in the center of the circuit. In contrast, arotor 48 (or spiral wave reentry) may involve the center 48A of thecircuit, and the circuit can be continuously varying and not following auniquely defined pathway. For rotors 48 and ectopic foci 46, thefrequency of a wave will generally decrease as it moves farther from thecenter of the ectopic focus 46A or rotor center 48A. That is, a mappingelement 24 positioned proximal the center 46A of an ectopic focus 46 orrotor center 48A will record a greater depolarization frequency than amapping element 24 positioned a greater distance from the center 46A ofthe ectopic focus 46 or rotor center 48A. Further, the one or moremapping elements 24 may each record a direction of a curved propagatingwave, which data is used by the computer 42 to calculate the rotorpattern. For reentrant loops 52, the circuit may define a discretepathway having a width. Particularly if the width is narrow, smallrelocations of the device distal portion 20 may detect the pathway,which will have a frequency that is independent of neighboring tissue.An optimal ablation site for a reentrant loop 52 is anywhere within theloop 52 that will disrupt the conduction loop or pathway. Thus, FIG. 4the center of the reentrant loop 52 is not represented by a small blackcircle as in FIGS. 2 and 3, because the center of the reentrant loop 52may not be the optimal ablation site.

Now referring to FIGS. 5 and 6, stylized representation of a distalportion 20 of a medical device 12 (depicted as a rectangle) placed adistance from the center 46A of an ectopic focus 46 and a rotor center48A are shown, respectively. The representations in FIGS. 5 and 6 (suchas arrows, rectangles, and black circles) are the same as in FIGS. 2-4.The propagating waves may move outward from the center 46A of theectopic focus 46 in any direction or in any pattern away from thecentral point in a rotor, but the frequency of a wave will generallydecrease as it moves farther from the center 46A of the ectopic focus 46or rotor center 48A. Using the morphological and directionalcharacteristics of one or more propagating waves sensed by the one ormore mapping elements 24 and communicated to the computer 42, thecomputer 42 may communicate to the user (via one or more screens orother displays 44) suggested treatment sites, or at a minimum a generaldistance and direction that might allow the user to move closer to theorigin of the ectopic focus 46 or rotor 48. Using the algorithmdiscussed above, the computer 42 may continue to suggest treatment sitesuntil an optimal treatment site, a site substantially at the center 46Aof an ectopic focus 46, rotor center 48A, or reentrant loop 52, islocated.

Now referring to FIG. 7, a first embodiment of a distal portion 20 of amedical device 12 with mapping and ablation functionality is shown. Thedistal portion 20 may have a coil or concentric spiral configuration 54with a plurality of turns. The coil or concentric spiral 54 may lie in aplane that is substantially orthogonal to the longitudinal axis 28 ofthe device 12. Each turn includes an anterior face 56, on which ispositioned one or more mapping elements 24 and/or one or more treatmentelements 26. If the spiral 54 is the treatment element 26, then the face56 of the spiral 54 may only contain mapping elements 24. To enhancesurface area and tissue contact, the one or more mapping 24 and/ortreatment elements 26 may have a curved or semi-circular profile thatextends from the anterior face 56 of each turn of the spiral 54 (forexample, as shown in FIG. 11). As a non-limiting example, as shown inFIG. 7, the spiral 54 is the treatment element 26 on which a pluralityof mapping elements 24 are borne. The mapping elements 24 may have acurved or semi-circular profile that extends from the anterior face 56of each turn of the spiral 54. Alternatively, the one or more mapping 24and/or treatment elements 26 may be set within and flush with theanterior face 56 of each turn (for example, as shown in FIG. 12). Thedistal portion 20 may be affixed to a shaft 58 that is slidably movablewithin the elongate body 18 of the device 12, or the distal portion 20may be continuous with the elongate body 18 of the device 12. Forexample, the distal portion 20 may include a cryoballoon coupled to theelongate body 18 that may be inflated with coolant to assume the coiledconfiguration shown in FIG. 7. Alternatively, the distal portion 20 maybe composed of a resilient and deformable material, and may assume afirst position for allowing passage through the vasculature to theregion of interest and a second extended position for mapping and/ortreatment. Further, the resilient and deformable material may be biasedtoward either the first or second position and may be steerable by oneor more pull wires, guide wires, rods, or other steering mechanismscontrollable at or proximal to the handle 16 of the device 12.Similarly, the distal portion 20 may be an elongated cryoablationelement that can assume a coiled configuration. For example, the distalportion 20 may include an inflatable element or balloon that, wheninflated, assumes the coiled configuration. Further, the balloon maybear one or more mapping 24 and/or treatment 26 elements on an outersurface (used, for example, for RF ablation, microwave ablation,ultrasound ablation, electroporation, or other treatment method), or mayenclose a coolant so the balloon may be used to cool and/or ablate atarget tissue area. The one or more treatment elements 26 may be influid communication with a coolant reservoir 34 and/or may be cooledusing a thermoelectric cooler or cryogenic fluid. Additionally oralternatively, the one or more treatment elements 26 may be capable oftransmitting RF, laser, ultrasound, or microwave energy, or the like.

Now referring to FIG. 8, a second embodiment of a distal portion 20 of amedical device 12 with mapping 24 and ablation functionality is shown.The distal portion 20 may include a crossed-arm array 60 that includes aplurality of arms 62, each of which bearing one or more mapping 24and/or treatment elements 26 at an anterior face 64 of the array 60.Each arm 62 may include a first portion 66 at the anterior face 64 ofthe array 60 on which the one or more mapping 24 and/or treatmentelements 26 are borne, and a second portion 68 that is coupled to thedevice 12. Each electrode may serve a mapping and/or ablation function,and it is conceived that mapping elements 24 may protrude fromunderlying ablative structures (as shown and described in FIGS. 11 and13). The point at which the first 66 and second 68 portion of each arm62 meet may form an acute angle. The second portion 68 of each arm 62may be affixed to a shaft 58 that is slidably movable within theelongate body 18 of the device 12, or affixed directly to the elongatebody 18. To enhance surface area and tissue contact, the one or moremapping 24 and/or treatment elements 26 may have a curved orsemi-circular profile that extends from the first portion 66 of each arm62 (for example, as shown in FIG. 10). Alternatively, the one or moremapping 24 and/or treatment elements 26 may be set within and flush withthe first portion 66 of each arm 62 (for example, as shown in FIG. 11).Each element may be capable of both mapping and ablation. Alternatively,for example, the mapping element 24 may protrude farther from the centerpoint 69 of the cross-arm array 60 to enhance tissue contact and signalquality, whereas the treatment elements 26 may cover a larger“footprint” for ablation of larger areas of tissue. Further, the distalportion 20 may be composed of a resilient and deformable material, andmay assume a first position for delivery (not shown) and a secondposition for mapping and/or treatment (as shown in FIG. 8). When in thesecond expanded position, the first portion 66 of each arm 62 may lie ina plane that is substantially orthogonal to the longitudinal axis 28 ofthe device 12. Still further, the resilient and deformable material maybe biased toward either the first or second position and may besteerable by one or more pull wires, guide wires, rods, or othersteering mechanisms controllable at or proximal to the handle 16 of thedevice 12. The one or more treatment elements 26 may be in fluidcommunication with a coolant reservoir 34 and/or may be cooled using athermoelectric cooler or cryogenic fluid. Alternatively, the one or moretreatment elements 26 may be capable of transmitting RF, laser,ultrasound, microwave, electroporation energy, or the like.

Now referring to FIG. 9, a third embodiment of a distal portion 20 of amedical device 12 with mapping and ablation functionality is shown. Thedevice 12 may be a focal catheter or similar device, without a distalarray or configuration and the one or more mapping 24 and/or treatmentelements 26 (referred to in FIG. 9 as “24/26”) being borne along thedistal portion 20 of the elongate body 18. Alternatively, the distalportion 20 of the device 12 may be composed of a material different thanthat of the elongate body 18, may have a different diameter or rigidity,or the like. To enhance surface area and tissue contact, the one or moremapping 24 and/or treatment elements 26 may have a curved orsemi-circular profile that extends from the distal portion 20 (forexample, as shown in FIG. 10). Alternatively, the one or more mapping 24and/or treatment elements 26 may be set within and flush with the distalportion 20 (for example, as shown in FIG. 11). Additionally, the distalportion 20 may be composed of a resilient and deformable material thatpermits bending of the distal portion 20, such as into a right-angle (orother acute or obtuse angle) bend, as depicted in dashed lines in FIG.9. The one or more mapping 24 and/or treatment elements 26 may bedisposed longitudinally along the distal portion 20. The one or moretreatment elements 26 may be in fluid communication with a coolantreservoir and/or may be cooled using a thermoelectric cooler orcryogenic fluid. Additionally or alternatively, the one or moretreatment elements 26 may be capable of transmitting RF, laser,ultrasound, microwave, electroporation energy, or the like. When mappingcardiac tissue, the distal portion 20 may either be oriented or bent toposition one or more mapping elements 24 in contact with the tissue (forexample, in a linear pattern). When treating cardiac tissue (either withlethal or sub-lethal temperatures), the device 12 may be used like afocal catheter to create a substantially circular focal lesion (such aswhen only the distal tip is placed in contact with the treatment site)or bent to create a substantially linear lesion (such as when alongitudinal surface of the distal portion 20 including two or moretreatment elements 26 is placed in contact with the treatment site).

Now referring to FIG. 10, a fourth embodiment of a distal portion 20 ofa medical device 12 with mapping and ablation functionality is shown.The distal portion 20 may include an array 70 that includes one or morearms 72 bearing one or more mapping 24 and/or treatment elements 26.Each arm 72 may include a first portion 76 at the anterior face 74 ofthe array 70 on which the one or more mapping 24 and/or treatmentelements 26 are borne, and a second portion 78 that is coupled to thedevice 12. The array 70 may further include one or more referenceelectrodes 30. As shown in FIG. 10, the one or more treatment elements26 may each include a mapping element 24, which may protrude from thecorresponding treatment element 26. The point at which the first 76 andsecond 78 portion of each arm 72 meet may form an acute angle. Thesecond portion 78 of each arm 72 may be affixed to a shaft 58 that isslidably movable within the elongate body 18 of the device 12, oraffixed directly to the elongate body 18. The cross-section of eachtreatment element 26/mapping element 28 combination may be as shown indetail in FIG. 13. Further, the distal portion 20 may be composed of aresilient and deformable material, and may assume a first position fordelivery (not shown) and a second position for mapping and/or treatment(as shown in FIG. 10). When in the second expanded position, the firstportion 76 of each arm 72 may lie in a plane that is substantiallyorthogonal to the longitudinal axis 28 of the device 12. Still further,the resilient and deformable material may be biased toward either thefirst or second position and may be steerable by one or more pull wires,guide wires, rods, or other steering mechanisms controllable at orproximal to the handle 16 of the device 12. The one or more treatmentelements 26 may be in fluid communication with a coolant reservoir 34and/or may be cooled using a thermoelectric cooler or cryogenic fluid.Additionally or alternatively, the one or more treatment elements 26 maybe capable of transmitting RF, laser, ultrasound, or microwave energy,or the like.

Now referring to FIGS. 11 and 12, cross sections of a first embodimentand a second embodiment of a mapping element 24 such as in FIGS. 7, 8,and 9 are shown. The cross section is taken along line A-A of FIGS. 7-9.As described above, the one or more mapping 24 and/or treatment elements26 (referred to as “24/26” in FIGS. 11 and 12) may have a curved orsemi-circular profile that protrudes from the device 12 or portionthereof (for example, array arm, elongate body, or the like) in order toenhance surface area and tissue contact (as shown in FIG. 11).Alternatively, the one or more mapping 24 and/or treatment elements 26may be set within and flush with the device 12 (as shown in FIG. 12).

Now referring to FIG. 13, a perspective view of a third embodiment of amapping element 24 such as in FIG. 10 is shown. The one or moretreatment elements 26 may each include a mapping element 24 protrudingtherefrom. Further, an insulative layer 80 may be included thatsurrounds each mapping element 24 to electrically isolate it relative tothe treatment element 26 and thus reduce the region of tissue from whichelectrical activity is sensed. The insulative layer 80 may also act toat least partially shield the one or more mapping elements 24 fromenergy transmitted by the one or more treatment elements 26.

Now referring to FIG. 14, a fifth embodiment of a distal portion 20 of amedical device 12 with mapping and ablation functionality is shown. Thedistal portion 20 may include an inflatable element or balloon 82 onwhich a plurality of electrodes 84 are borne. For example, theelectrodes 84 may be small button electrodes that are affixed to theouter surface of the balloon 82. The electrodes 84 may be affixed to ananterior face 86 of the balloon 82, and they may be affixed in aradially symmetrical pattern. The electrodes 84 may be used to map andablate an area of target tissue. Additionally or alternatively, theelectrodes 84 may be used to map tissue, whereas ablation of the tissueis accomplished through the use of a coolant that is circulated withinthe balloon lumen 88.

It will be understood that any of the above devices may be used to applyelectroporation energy to the cells of the area of target tissue.Electroporation utilizes high electric field amplitude electrical pulsesto effectuate a physiological modification (i.e. permeabilization) ofthe cells to which the energy is applied. Such pulses may preferably beshort (for example, having a nanosecond, microsecond, or millisecondpulse width) in order to allow application of high voltage without alarge flow of electrical current that would result in significant tissueheating. In particular, the pulsed energy induces the formation ofmicroscopic pores or openings in the cell membrane. Depending on thecharacteristics of the electroporation pulses, an electroporated cellcan survive electroporation (referred to as “reversibleelectroporation”) or be killed by electroporation (referred to as“irreversible electroporation” or “IEP”). Reversible electroporation maybe used to transfer agents, including large molecules, into targetedcells for various purposes. Thus, electroporation may be used to disabletissue cells, ablate tissue cells, or prepare tissue cells forsubsequent therapies, such as gene delivery, protein delivery, ordelivery of other therapeutic agents or substances intended to modifythe behavior of the target tissue cells.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed herein above. In addition, unless mention was made above tothe contrary, it should be noted that all of the accompanying drawingsare not to scale. A variety of modifications and variations are possiblein light of the above teachings without departing from the scope andspirit of the invention, which is limited only by the following claims.

What is claimed is:
 1. A method of locating and treating a source orpathway of electrical conduction within cardiac tissue, the methodcomprising: (a) positioning one or more mapping elements affixed to adistal end of medical device in contact with cardiac tissue at a firstposition, the medical device being in communication with a controlsystem including a computer having a display and programmable to executealgorithms, the cardiac tissue being composed of cells; (b) executingcomputer algorithms to determine directional and morphological featuresof the electrical conduction of interest based at least in part onsignals received by the computer from the one or more mapping elementsat the first position; (c) displaying on the computer display asuggested second position at which the one or more mapping elementsshould be placed in contact with the cardiac tissue; (d) repositioningthe one or more mapping elements at the second position; (e) executingcomputer algorithms to determine directional and morphological featuresof the electrical conduction of interest based at least in part onsignals received by the computer from the one or more mapping elementsat the second position; (f) repeating steps (a)-(e) until a source orpathway of the electrical conduction of interest is located; and (g)activating one or more treatment elements in contact with the cardiactissue cells to treat the cells at a non-lethal temperature and disruptthe source or pathway of the electrical conduction of interest, the oneor more mapping elements protrude from the one or more treatmentelements, at least a portion of the plurality of mapping elements havingan insulative layer that electrically isolates the mapping element fromthe treatment element from which it protrudes.
 2. The method of claim 1,wherein the one or more treatment elements cools or heats the cardiaccells at the source or pathway of electrical conduction of interest to anon-lethal temperature.
 3. The method of claim 1, further comprisingtreating the cardiac cells at the source or pathway of the electricalconduction of interest at a lethal temperature.
 4. The method of claim3, wherein treating the cardiac cells at the source or pathway of theelectrical conduction to a lethal temperature includes at least one ofcryoablation, tissue cooling, applying radiofrequency energy, applyinglaser energy, applying microwave energy, applying laser energy, andapplying ultrasound energy.
 5. The method of claim 1, further comprisingelectroporating the cardiac cells at source or pathway of the electricalconduction of interest with pulses of high voltage energy.
 6. The methodof claim 5, further comprising delivering to the cardiac cells at thesource or pathway of the electrical conduction of interest one or moresubstances from the group consisting of genes, proteins, drug therapysubstances, agents that modify the behavior of the cells, andcombinations thereof.
 7. The method of claim 3, wherein the cardiaccells at the source or pathway of the electrical conduction of interestare treated at a lethal temperature only after treating the cardiaccells at the source or pathway of the electrical conduction of interestat a non-lethal temperature.
 8. The method of claim 3, wherein treatingthe cardiac cells at the source or pathway of electrical conduction ofinterest at a lethal temperature terminates the electrical conduction ofinterest.
 9. A method of locating and treating a source or pathway ofelectrical conduction within cardiac tissue, the method comprising: (a)positioning one or more mapping elements affixed to a distal end of amedical device in contact with cardiac tissue at a first position, themedical device being in communication with a control system including acomputer having a display, the cardiac tissue being composed of cells;(b) executing computer algorithms to determine directional andmorphological features of the electrical conduction of interest based atleast in part on signals received by the computer from the one or moremapping elements at the first position; (c) displaying on the computerdisplay a suggested second position at which the one or more mappingelements should be placed in contact with the cardiac tissue; (d)repositioning the one or more mapping elements at the second position;(e) executing computer algorithms to determine directional andmorphological features of the electrical conduction of interest based atleast in part on signals received by the computer from the one or moremapping elements at the second position; (f) repeating steps (a)-(e)until a the source of the electrical conduction of interest is located;(g) activating one or more treatment elements in contact with thecardiac tissue cells to treat the cells at a non-lethal temperature,where the one or more mapping elements protrude from the one or moretreatment elements, at least a portion of the plurality of mappingelements having an insulative layer that electrically isolates themapping element from the treatment element from which it protrudes; and(h) if (g) disrupts the source or pathway of the electrical conductionof interest, activating the one or more treatment elements in contactwith the cardiac tissue cells to perform at least one of treating thecells with a lethal temperature and electroporating the cells.
 10. Amethod of locating and treating a source or pathway of electricalconduction within cardiac tissue, the method comprising: (a) positioninga medical device, the medical device including: at least one array armand a plurality of electroporation treatment elements coupled to the atleast one array arm; a plurality of mapping elements, each of theplurality of electroporation treatment elements having a correspondingone of the plurality of mapping elements protruding therefrom, at leasta portion of each of the plurality of mapping elements having aninsulative layer that electrically isolates the mapping element from thetreatment element from which it protrudes, the medical device beingpositioned such that at least one of the plurality of mapping elementsis in contact with cardiac tissue at a first position, the medicaldevice being in communication with a control system including a computerhaving a display and programmable to execute algorithms, the cardiactissue being composed of cells; (b) executing computer algorithms todetermine a morphology and a directionality of the electrical conductionof interest based at least in part on signals received by the computerfrom the plurality of mapping elements at the first position; (c)displaying on the computer display a suggested optimal treatment site;and (d) activating at least one of the plurality of electroporationtreatment elements in contact with the cardiac tissue cells to treat thecardiac tissue cells with electroporation energy to disrupt the sourceor pathway of the electrical conduction of interest.
 11. The method ofclaim 10, wherein the at least one of the plurality of electroporationtreatment elements reversibly electroporates the cardiac tissue cells.12. The method of claim 10, wherein activating the at least one of theplurality of electroporation treatment elements includes deliveringelectroporating the cardiac tissue cells with pulses of high voltageenergy.
 13. The method of claim 10, further comprising, after (b):(b)(i) displaying on the computer display a suggested second position atwhich the at least one of the plurality of mapping elements should beplaced in contact with the cardiac tissue; (b)(ii) repositioning the atleast one of the plurality of mapping elements at the second position;(b)(iii) executing computer algorithms to determine morphology anddirectionality of the electrical conduction of interest based at leastin part on signals received by the computer from the at least one of theplurality of mapping elements at the second position; and (b)(iv)repeating steps (a)-(e) until a source or pathway of the electricalconduction of interest is located.
 14. The method of claim 13, furthercomprising: (e) delivering to the cardiac tissue cells at the source orpathway of the electrical conduction of interest one or more substancesfrom the group consisting of genes, proteins, drug therapy substances,agents that modify a behavior of the cells, and combinations thereof.15. The method of claim 13, wherein activating at least one of theplurality of electroporation treatment elements in contact with thecardiac tissue cells to treat the cardiac tissue cells withelectroporation energy terminates the electrical conduction of interest.16. The method of claim 10, wherein each of the plurality of mappingelements is configured to record monophasic action potentials and totransmit to the control system at least one of depolarization timing,repolarization timing, action potential morphology, and action potentialduration.
 17. The method of claim 10, wherein the medical device furtherincludes a longitudinal axis and each of the at least one array armincludes a first portion and a second portion, the first portion beingin a plane that is substantially orthogonal to the longitudinal axis ofthe medical device.
 18. The method of claim 10, wherein the plurality ofmapping elements are arranged in a radially symmetrical pattern.